Asphalt built up layer roofing (BUR) is primarily applied by moping 450° F. to 475° F. asphalt (petroleum distillate) or bitumen (naturally occurring coal tar) to a substrate and covering with felt paper in multiple layers. One hundred pound cylinders of material are broken with a sledge and shoveled into an under-fired gas or electric melting kettle. The surface of the vessel necessarily exceeds the target melt temperature of the thermally slow conducting material. This results in the liberation of odiferous and potentially carcinogenic smoke. The molten material is transported to the rooftop by heated pump and tubing to the application site and distributed with rag mops.
The current execution of this process is essentially the same as previously practiced for over 100 years. In recent years advances have been made in added smoke abatement equipment and material additives to coat the surface of the kettle melt.
The purpose of this invention is to replace the current apparatus and method of melting and distributing asphalt. The primary embodiment of the invention melts industry standard 100-pound cylinders of asphalt in a vertical orientation at the moving site of application. The asphalt is placed on a perforated metal disc that is magnetic induction heated to the target temperature. The material melts at this interface and is distributed to the substrate at a controlled rate, as the felt paper is unrolled to form a layer of the BUR roofing system. A wheeled carriage with a balancing pressure roller, of felt paper width, rides on the unrolling felt paper and disperses the asphalt melt flow. Continuously melting asphalt, high frequency induction heating power supply, rolled felt paper, and an electric motor to power the wheels are positioned on this carriage. The volume of asphalt melted is controlled to match the traverse speed of the unit. The hot asphalt flow can be stopped and restarted in seconds. An operator guides the unit and replenishes the felt paper and asphalt cylinder as required. The appliance is powered by flexible cable from a portable electric generator placed on the rooftop or at ground level as required by size.
This system provides the advantages of minimum exposure of melted material, controlled distribution, simultaneous application of the felt paper, avoids the smoke producing over heating, minimizes labor required and enhances job-site safety and energy efficiency.
A second embodiment of the invention is intended to address applications of rubberized asphalt and polymer asphalt blends that are placed to fill concrete highway expansion cracks and asphalt highway cracks, depressions for traffic control loops, and adhere highway reflective markers. Many of these compounds are currently distributed as briquettes to melt in hot oil heated tanks utilized to avoid local overheating. There would not be any economic disadvantage for material suppliers to package in cylinders to accommodate this superior method of melting. The same advantages of melt on demand, energy efficiency, safety and melt temperature control are present here.